From the Guidelines
Iron transfusions prior to surgery are typically recommended for patients with iron deficiency anemia, defined as hemoglobin levels below 13 g/dL for men and below 12 g/dL for women, with ferritin levels below 100 ng/mL indicating iron deficiency, as stated in the 2024 AHA/ACC/ACS/ASNC/HRS/SCA/SCCT/SCMR/SVM guideline for perioperative cardiovascular management for noncardiac surgery 1.
Key Points
- The guideline recommends iron therapy, either oral or intravenous, for patients with iron deficiency anemia having elective noncardiac surgery to reduce blood transfusions and increase hemoglobin 1.
- A ferritin concentration <100 ng/mL, transferrin saturation <20%, and/or microcytic hypochromic red cells are indicative of iron deficiency 1.
- Preoperative iron optimization is particularly important for major surgeries with expected blood loss exceeding 500 mL, including cardiac, orthopedic, major abdominal, gynecological, and oncological procedures.
- The recommended approach is intravenous iron administration, with common formulations including iron sucrose, ferric carboxymaltose, and iron dextran, with treatment ideally beginning 2-4 weeks before surgery to allow adequate time for erythropoiesis.
Surgeries Requiring Iron Transfusion
- Cardiac surgery
- Orthopedic surgery (especially joint replacements)
- Major abdominal surgery
- Gynecological surgery
- Oncological surgery
Benefits of Preoperative Iron Optimization
- Reduces the need for allogeneic blood transfusions
- Decreases postoperative infection rates
- Shortens hospital stays
- Improves overall surgical outcomes
- Particularly valuable in patients who cannot tolerate oral iron supplements or when surgery cannot be delayed long enough for oral supplementation to be effective, as supported by the ERAS® society recommendations for elective colorectal surgery 1.
From the Research
Guidelines for Iron Transfusion Prior to Surgery
The guidelines for iron transfusion prior to surgery are based on the patient's iron status and the type of surgery they are undergoing.
- According to the study 2, pre-operative anaemia is defined by a haemoglobin level < 130 g/l, and absolute iron deficiency is defined by ferritin < 30 ng/ml.
- The study 3 defines anaemia as haemoglobin values less than 13 g/dL for males and 12 g/dL for non-pregnant females.
Ferritin Cutoff for Iron Transfusion
The ferritin cutoff for iron transfusion varies depending on the study.
- The study 2 defines absolute iron deficiency by ferritin < 30 ng/ml.
- The study 4 defines iron deficiency as ferritin 100-300 μg/L along with transferrin saturation (TSAT) < 20%.
- The study 5 does not specify a ferritin cutoff for iron transfusion.
Surgeries that Require Iron Transfusion
The surgeries that require iron transfusion are those that are associated with significant blood loss or pre-operative anaemia.
- The study 2 includes patients undergoing elective orthopaedic surgery, cardiac surgery, colorectal cancer resection, radical prostatectomy, gynaecological surgery, or resection of liver metastases.
- The study 4 includes patients undergoing major surgeries, including emergency and elective interventions.
- The study 5 includes patients undergoing elective cardiac surgery.
- The study 6 includes patients with refractory anemia, and the treatment with ferric carboxymaltose and erythropoiesis-stimulating agents reduces the rate of blood transfusion.
Effectiveness of Iron Therapy
The effectiveness of iron therapy in reducing the need for allogeneic blood transfusions is still uncertain.
- The study 3 shows that iron therapy does not reduce the proportion of patients who receive a blood transfusion.
- The study 5 shows that intravenous or oral iron supplementation is ineffective in correcting anaemia after cardiopulmonary bypass and does not reduce blood transfusion requirements.
- The study 6 shows that the addition of iron to erythropoiesis-stimulating agents reduces the rate of blood transfusion in patients with refractory anemia.